In the starting position, go forward and take a chaingun. However, enemies will be unleashed here but they are not alerted. You can cause an infight between arachnotron and zombies but this will be difficult to not loose health. After you deal with them, go forward to the outside and drop down. Take the super shotgun and drop to the lava below. From here you can glimpse a courtyard but first you need to obtain the key. Turn left and use the lift which will bring you to another courtyard. Go forward and turn left to see a door which is locked. Instead, use either path here and you will eventually come to a blue key courtyard.

Walk on the stairs to get the key within the structure. You will be trapped here, as an ambush will be opened. You can fight the enemies while being trapped or shoot the button in the southeastern trap alcove where one of the imps is. You will be freed but to get out fight all the enemies here. Go back to the northern courtyard and then to the eastern one.

Blue key (alternative path)

Alternatively, you can use another path towards the blue key. It is recommended if this is a pistol start game, as you can obtain more ammo there. Plus, you can find your first two secrets (secret #1 and secret #2).

In the starting position, go forward and take a chaingun. However, enemies will be unleashed here but they are not alerted. You can cause an infight between arachnotron and zombies but this will be difficult to not loose health. After you deal with them, go forward to the outside but do not drop down yet. Instead, turn left and jump over from one ledge to the other. You will see several lava falls and a large platform with mancubus upon it. Walk behind this platform and you will find a lift. Use the lift to get into a room with super shotgun. However, beware a chaingunner ambush. Enter the next room in which press the switch and you will be lowered. Now, you can visit the courtyard in which the blue key is located.

Walk on the stairs to get the key within the structure. You will be trapped here, as an ambush will be opened. You can fight the enemies while being trapped or shoot the button in the southeastern trap alcove where one of the imps is. You will be freed but to get out fight all the enemies here. Go to the courtyard which is north from here. Head to the right and drop into the shaft. Ahead is another courtyard which requires you to have the blue key.

Yellow key

Once in the eastern courtyard, push the skull switch. So, you reveal a very large group of imps behind the wall. Eventually, after all the enemies fought take the yellow card on its pedestal and turn right and open the wall. Use the orange teleporter, your shortcut to the western courtyard.

Once you will be in that courtyard, use the lift which will bring you to the door by pressing its switch. The lift requires you to have yellow key. Open the door and you will be in a room with a lava pool in the middle. To the left and right are the enemies, one Hell knight and one or two mancubi on each side. If you are playing on Hurt me plenty skill level, you can cause an infight between them to ease your main objective. Unfortunately, on hard, and even on easy, skill levels there is only one type of enemy, the mancubi. So, the infight is impossible. The room is separated into wing parts. Turn left and go to the left wing and press the skull switch. Go to the right wing to reveal even more enemies. Fight them and head into an open room. Step on the portal to finish the level.

In the starting area, drop down and head immediately to the right. There is a shaft leading to a cave. Jump down there. If you press the switch on the lava, it will lower two platforms, one having the rocket launcher and the second having four rockets. The button also opens an ambush.

In the start, turn right and walk behind the closest beige column. Push the wall and take clips and shotgun. (sector 421)

From the starting area, head forward and not dropping down turn left. Go behind the raised platform with mancubus. You can see the lift and the button for activating it but you actually can go deeper to the right in the narrow space between rock and the platform's side. There is a tiny green button. Push it and go back around the platform to see the metal bars opened. They previously hid the berserk behind. Take the berserk pack. (sector 49)

Right here, where secret #2 and mancubus platform are, go behind the platform back again. Use the lift and go forward to the dark room with the switch. Press the switch and the floor below you will go down. To the left is an orange teleporter and two imps. Use the teleporter and you will be brought back to the previous room standing on another teleporter. Reuse this second one and you will be deposited on the raised platform seen before. From here do a run jump towards the ground which is inaccessible from lower levels. Grab various ammunition. (sector 363)

From the starting area, head forward and drop to the lava below. Go to the lift that connects western and eastern parts of the level and a raised platform with a revenant or imp. There is actually a room below the platform. To get there, step on the wooden staircase that leads to the lift (you do not need the lift itself) and do a run-jump over brick sill. Once you fall down you will be able to go to a small area with ammo clips and some enemies. Enter the cave and enter the orange teleporter taking the soul sphere upon it. You will be brought to a bizarre room with large sigil, reminding a spiral, printed on the floor (and probably on ceiling). (sector 309) A large group of enemies infests this room but they cannot see you, as they turned back to you. The main goal is to take four plasma guns and get out of the room by pressing the switch at the northwestern corner of the room. The switch glows, so it can sometimes be lost of your sight. There are also two boxes of shells on the hard skills. Eliminate all the enemies in the room and press the aforementioned switch. The teleporter will open but an arch-vile can be here on UV and Nightmare! but it is unable to get to the center of the room and resurrect enemies. Use the teleporter to get out of the room.

In the room with the blue switch (and yellow key) a tiny hidden switch in the far corner of the room gives access to a soul sphere. (sector 178)

Go to the northeastern courtyard where a skull button which requires blue key is. Walk to the southeastern corner, and you will find a green button. Press it, and the ledge next to you will lower letting you to drop to lava below. Drop there and head left (south). There will be a soul sphere. Taking the sphere will bring you to the rocket launcher cave.

In the western courtyard in which there is lift requiring yellow key, press a switch on the northern wall, and a teleporter will open. Enter it and you will be on the ledge with imp and sergeants. Right from here you can go to the western courtyard via the raised platform with backpack or super shotgun.